1. Field of the Invention
The present invention relates to an exposure device, and in particular to an exposure device that conducts digital exposure with high precision using evanescent light.
2. Description of the Related Art
In recent years, various evanescent light heads that conduct high-density recording and microfabrication using evanescent light have been proposed. For example, an exposure head has been proposed where micro-openings are formed in tapered tips of optical fibers and laser light is introduced from the other ends to expose a photosensitive material using evanescent light leaking out from the micro-openings (Japanese Patent Application Laid-Open Publication (JP-A) No. 2002-123965, paragraphs 38–39, and FIG. 8). In this exposure head, optical fiber cores are two-dimensionally arranged, and laser light is introduced to the optical fiber cores of positions corresponding to the bit pattern of information to be written. Also, as a light head whose manufacture is simple, an evanescent light head where a light-blocking film including micro-openings is disposed at the light-emitting side of a lens array has been proposed (JP-A No. 2000-228554).
However, JP-A No. 2002-123965 does not disclose specific means for introducing the laser light to the optical fiber cores of the positions corresponding to the bit pattern of the information. The diameter of the optical fiber cores is about several microns, and there is the problem that it is difficult to introduce the laser light to each of the two-dimensionally arranged optical fiber cores with a high coupling efficiency.
JP-A No. 2000-228554 also does not disclose specific means for introducing the laser light to the lens array. In this case also, it is difficult to match the optical axes to each lens of the lens array and introduce the laser light thereto.